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Codebook for NHGIS data file 'nhgis0003_ts_nominal_county'
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Contents
    - Data Summary
    - Data Dictionary
    - Geographic Integration Methods
    - Source Data
    - Citation and Use
 
Detailed notes on time series design and comparability are available at: 
    https://data2.nhgis.org/main/all_tst_details 
 
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Data Summary
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Time series layout:     Time varies by column
Geographic level:       County (by State)
Geographic integration: Nominal
Measurement times:      1980, 1990, 2000, 2006-2010, 2007-2011, 2008-2012, 2009-2013, 2010-2014, 2011-2015, 2012-2016, 2013-2017, 2014-2018, 2015-2019, 2016-2020, 2017-2021, 2018-2022, 2019-2023, 2020-2024
Extent:                 All areas
 
Tables:
 
1. Median Household Income in Previous Year
   Selected year(s): 1980, 1990, 2000, 2006-2010, 2007-2011, 2008-2012, 2009-2013, 2010-2014, 2011-2015, 2012-2016, 2013-2017, 2014-2018, 2015-2019, 2016-2020, 2017-2021, 2018-2022, 2019-2023, 2020-2024
   Code: B79
 
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Data Dictionary
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Context Fields 
        GISJOIN:     GIS Join Match Code
        STATE:       NHGIS Integrated State Name
        STATEFP:     FIPS State Code
        STATENH:     NHGIS Integrated State Code
        COUNTY:      NHGIS Integrated County Name
        COUNTYFP:    FIPS County Code
        COUNTYNH:    NHGIS Integrated County Code
 
Table 1: (B79) Median Household Income in Previous Year
    Time series AA: Median income in previous year: Households
        B79AA1980:   1980: Median income in previous year: Households
        B79AA1990:   1990: Median income in previous year: Households
        B79AA2000:   2000: Median income in previous year: Households
        B79AA105:    2006-2010: Median income in previous year: Households
        B79AA105M:   Margin of error: 2006-2010: Median income in previous year: Households
        B79AA115:    2007-2011: Median income in previous year: Households
        B79AA115M:   Margin of error: 2007-2011: Median income in previous year: Households
        B79AA125:    2008-2012: Median income in previous year: Households
        B79AA125M:   Margin of error: 2008-2012: Median income in previous year: Households
        B79AA135:    2009-2013: Median income in previous year: Households
        B79AA135M:   Margin of error: 2009-2013: Median income in previous year: Households
        B79AA145:    2010-2014: Median income in previous year: Households
        B79AA145M:   Margin of error: 2010-2014: Median income in previous year: Households
        B79AA155:    2011-2015: Median income in previous year: Households
        B79AA155M:   Margin of error: 2011-2015: Median income in previous year: Households
        B79AA165:    2012-2016: Median income in previous year: Households
        B79AA165M:   Margin of error: 2012-2016: Median income in previous year: Households
        B79AA175:    2013-2017: Median income in previous year: Households
        B79AA175M:   Margin of error: 2013-2017: Median income in previous year: Households
        B79AA185:    2014-2018: Median income in previous year: Households
        B79AA185M:   Margin of error: 2014-2018: Median income in previous year: Households
        B79AA195:    2015-2019: Median income in previous year: Households
        B79AA195M:   Margin of error: 2015-2019: Median income in previous year: Households
        B79AA205:    2016-2020: Median income in previous year: Households
        B79AA205M:   Margin of error: 2016-2020: Median income in previous year: Households
        B79AA215:    2017-2021: Median income in previous year: Households
        B79AA215M:   Margin of error: 2017-2021: Median income in previous year: Households
        B79AA225:    2018-2022: Median income in previous year: Households
        B79AA225M:   Margin of error: 2018-2022: Median income in previous year: Households
        B79AA235:    2019-2023: Median income in previous year: Households
        B79AA235M:   Margin of error: 2019-2023: Median income in previous year: Households
        B79AA245:    2020-2024: Median income in previous year: Households
        B79AA245M:   Margin of error: 2020-2024: Median income in previous year: Households
 
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Geographic Integration Methods
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Nominal Integration:

    Nominally integrated tables link geographic units across time according to
    their names and codes, disregarding any changes in unit boundaries. The
    identified geographic units match those from each census source, so the
    spatial definitions and total number of units may vary from one time to
    another (e.g., a city may annex land, a tract may be split in two, a new
    county may be created, etc.). The tables include data for a particular
    geographic unit only at times when the unit's name or code was in use,
    resulting in truncated time series for some areas.
    
    Users should be cautious when interpreting changes in nominally integrated
    time series because a single unit code may refer to distinctly different
    areas at different times. If you are uncertain whether any boundaries
    changed in your areas of interest, we recommend inspecting NHGIS GIS files
    to confirm. (NHGIS supplies GIS boundary files for all units and years in
    nominally integrated time series *except* 1970 places and county
    subdivisions.)
    
    Alternatively, for some topics and time periods, NHGIS provides
    "geographically standardized" time series, which provide data from multiple
    times for a single census's geographic units (e.g., 2000 and 2010 data for
    2010 census units). A disadvantage of standardized time series is that, in
    areas where source units do not nest perfectly within a unit of the standard
    year (e.g., where a source 2000 unit intersects multiple 2010 units), NHGIS
    applies interpolation to standardize the data, a process which may
    occasionally produce substantial errors.

Complete documentation on time series integration methods is available at:
    https://www.nhgis.org/documentation/time-series
 
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Source Data
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Additional documentation on NHGIS data sources is available at:
    https://www.nhgis.org/documentation/tabular-data

Table 1: (B79) Median Household Income in Previous Year
 
    Time series AA: Median income in previous year: Households
        Year: 1980
            Source dataset: 1980 Census: STF 3 - Sample-Based Data
                Source table: NT69. Median Household Income in 1979
                    Universe: Households
                        Variable: [DIE001] Median household income in 1979
        Year: 1990
            Source dataset: 1990 Census: STF 3 - Sample-Based Data
                Source table: NP80A. Median Household Income in 1989
                    Universe: Households
                        Variable: [E4U001] Median household income in 1989
        Year: 2000
            Source dataset: 2000 Census: SF 3a - Sample-Based Data [Areas Larger Than Block Groups]
                Source table: NP053A. Median Household Income in 1999
                    Universe: Households
                        Variable: [GMY001] Median income in 1999
        Year: 2006-2010
            Source dataset: 2010 American Community Survey: 5-Year Data [2006-2010, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2010 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [JOI001] Median household income in the past 12 months (in 2010 inflation-adjusted dollars)
        Year: 2007-2011
            Source dataset: 2011 American Community Survey: 5-Year Data [2007-2011, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2011 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [MP1001] Median household income in the past 12 months (in 2011 inflation-adjusted dollars)
        Year: 2008-2012
            Source dataset: 2012 American Community Survey: 5-Year Data [2008-2012, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2012 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [QU1001] Median household income in the past 12 months (in 2012 inflation-adjusted dollars)
        Year: 2009-2013
            Source dataset: 2013 American Community Survey: 5-Year Data [2009-2013, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2013 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [UHD001] Median household income in the past 12 months (in 2013 inflation-adjusted dollars)
        Year: 2010-2014
            Source dataset: 2014 American Community Survey: 5-Year Data [2010-2014, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2014 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [ABDP001] Median household income in the past 12 months (in 2014 inflation-adjusted dollars)
        Year: 2011-2015
            Source dataset: 2015 American Community Survey: 5-Year Data [2011-2015, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2015 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [ADNK001] Median household income in the past 12 months (in 2015 inflation-adjusted dollars)
        Year: 2012-2016
            Source dataset: 2016 American Community Survey: 5-Year Data [2012-2016, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2016 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [AF49001] Median household income in the past 12 months (in 2016 inflation-adjusted dollars)
        Year: 2013-2017
            Source dataset: 2017 American Community Survey: 5-Year Data [2013-2017, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2017 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [AH1P001] Median household income in the past 12 months (in 2017 inflation-adjusted dollars)
        Year: 2014-2018
            Source dataset: 2018 American Community Survey: 5-Year Data [2014-2018, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2018 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [AJZA001] Median household income in the past 12 months (in 2018 inflation-adjusted dollars)
        Year: 2015-2019
            Source dataset: 2019 American Community Survey: 5-Year Data [2015-2019, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2019 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [ALW1001] Median household income in the past 12 months (in 2019 inflation-adjusted dollars)
        Year: 2016-2020
            Source dataset: 2020 American Community Survey: 5-Year Data [2016-2020, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2020 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [AMR8001] Median household income in the past 12 months (in 2020 inflation-adjusted dollars)
        Year: 2017-2021
            Source dataset: 2021 American Community Survey: 5-Year Data [2017-2021, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2021 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [AOQI001] Median household income in the past 12 months (in 2021 inflation-adjusted dollars)
        Year: 2018-2022
            Source dataset: 2022 American Community Survey: 5-Year Data [2018-2022, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2022 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [AQP6001] Median household income in the past 12 months (in 2022 inflation-adjusted dollars)
        Year: 2019-2023
            Source dataset: 2023 American Community Survey: 5-Year Data [2019-2023, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2023 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [ASQP001] Median household income in the past 12 months (in 2023 inflation-adjusted dollars)
        Year: 2020-2024
            Source dataset: 2024 American Community Survey: 5-Year Data [2020-2024, Block Groups & Larger Areas]
                Source table: B19013. Median Household Income in the Past 12 Months (in 2024 Inflation-Adjusted Dollars)
                    Universe: Households
                        Variable: [AURU001] Median household income in the past 12 months (in 2024 inflation-adjusted dollars)
 
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Citation and Use of NHGIS Data
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        Jonathan Schroeder, David Van Riper, Steven Manson, Katherine Knowles, Tracy Kugler, Finn Roberts, and Steven Ruggles. 
        IPUMS National Historical Geographic Information System: Version 20.0 
        [dataset]. Minneapolis, MN: IPUMS. 2025. 
        http://doi.org/10.18128/D050.V20.0

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